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I had a curious experience with V4 High Amp. (

Bought it new from Andreas Rauenbuhler.

When receiving it, I connected it normally to my preamp, connected my Stax SR507 brand new (bought a month ago from Stax dealer in Germany), turned it on : a loud hum in right channel.

I mailed to Rauenbuhler, he told me to open amp and disconnect ground cable (possible ground loop). I did.

No change.

Now I made a strange experiment. I unplugged the amp from the preamp, plugged it to the mains in another room, still the hum. Then I unplugged totally the Stax from the amp and kept the headphones on my ears (headphones not plugged to the amp) and I touched the amp’s front : the buzzing sound became a deep humming, audible in the headphones ! My body was conducting current from the amp.:confused:


Result :

- humming was even deeper when knob volume to zero, and louder in R channel

- when turning knob volume to 40 %, humming becomes a buzz again, this time equal in strength in L and R channel

I returned the amp to Rauenbuhler and he said : with me, it works perfectly. :rolleyes:


What's that Gremlin ? :D 


PS : My system counts 7 units, and I never encountered any problem of the sort. Andreas is very experienced and got fave reviews for his units, so what gives ?

Edited by quantx - 2/22/14 at 8:30am